Placer mining



3 Sheets-Sheet I.

(No Model.)

S. S. HARPER'. PLACER MINING..

il? I Patented May '14, 1895.

NoI 539,054.

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3 Sheetssheetl 3 S.S.HARPBR.

PLACER MINING.

Patented May 14,v 1895.-

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(N0 Model) ad 'Mw NiTE STA/TES PATENT OFFICE.

SAMUEL s. HARPER, OE DENVER, COLORADO.'

PLACER MlNING.

SPECIFICATION forming part of Letters'Patent No. 539,054, dated May 14,1895.

Application led August 10, 1894.

To all whom it may concern:

Beit known that I, SAMUEL S. HARPER, of Denver, in the county ofArapahoe and State of Colorado, have invented a new and Improved Methodof Placer Mining, of Which the following is a full, clear, and exactdescription.

My invention relates to an improved method of placer mining, andincidentally to certain features of the apparatus used in connectionWith my method, and my method is particularly adapted to mining inplaces where ordinary means cannot be employed to advantage.

My method contemplates using a dredge to raise the gold-bearing graveland deliver it to a ilume or a series ofl sluice boxes, and to provide4means for draining the pit which the dredger digs, to the end that thegold which escapes the dredger and accumulates on the bed rock bottom ofthe pit may berecovered, this draining of the pit also enabling the bedrock to be scraped and all the gold secured.

In using dredgers in placer mining, diiticulty has heretofore beenexperienced in making a satisfactory connection between the dredger andthe flumes or sluice boxes, and myv method contemplates arrangingmovable flumes or sluice boxes so that they may be kept always in easycommunication with the dredger, so that the raised material may bedelivered into the said tlumes or sluice boxes without any considerableexpense and without Wasting material. Another difiiculty in this sort ofwork has been experienced in taking care of the tailings, but by mymethod a submerged dam is arranged across the pit, which holds thetailings in check and enables the pit to be drained and the bed rockscraped, as hereinafter specified. YIn this connection another novelfeature of my improved method consists in providing a channel which iskept flooded by a temporary dam, and in which the dredger may float andbe at work while the pit previously digged is having its bottom scraped.

To these ends my invention consists of an improved lmethod of placermining and certain novel apparatus for carrying said method into effect,all of which will be hereinafter fully described and claimed.

Reference is to be had to the accompanying drawings, forming a part ofthis specification,

Serial No. 519,987. (No model.)

in which similar figures of reference indicate corresponding parts inall the views.

Figure 1 is a diagram illustrating themanner in which my method iscarried out Where there is an adjacent stream to draw from. Fig. 2 is asectional view showing the arrangement of the dredger, the pit, and thedrain of the latter. Fig. 3 is a sectional elevation showing theposition of the dredger in the channel referred to while the working-pitis drained ready to have its bottom scraped. Fig. 4 is a similar viewshowing the arrangement of the pit after the submerged dam has beenerected to hold back the tailings and the dredger again floated in theWorking-pit, so as to remove the material which has been scraped up onthe pit bottom; and Fig. 5 is a cross-sectional view showing the meansfor adjusting the flume or sluice-boxesto suit the position of thedredger.

In carrying out my invention, an open ditch is begun at a point farenough below the ground proposed to be Worked, and this ditch runs at agrade barely sucient to allow water to flow through'it. When the saidditch has reached a depth of from ten to fourteen feet, it is continuedunderground in the form ot' a tunnel 10, until, by running at a lessergrade than the bed rock l1 of the placer, it eventually reaches the bedrock. This open cut and tunnel is for the purpose of draining the bedrockl-and the pit 12 which is dug above it.y When, however, the open cutand tunnel cannot be used to advantage, the pit may be drained by meansof a pump and suitable pipes. The tunnel l0 is continued into the pitalong the bed rock as the pit 1s dug, and the tunnel, which is in theform of a square Wooden box large enough to be entered and cleaned maybe held down by suitable bowlders and it has at its upper end acontrolling or head gate 16.

As illustrated in the drawings the pit is supplied With Water fromastream 13, and to enable the desired quantity of water to be provided,the stream is dammed, as shown at 14, and its course diverted through asupplemental channel 15 around the placer ground, which is being worked.The head gate is kept closed when the dredger 17 is being Worked, sothat the pit may till and float the dredger. The dredger may be of anyapproved kind ICO vto

and it is provided with a suitable dipper 19 and elevator 2O to deliverthe gravel, which it raises, into the fiume or sluice box 18 which iscarried on supports 19Eb on the dredger, is held at an inclination, isadapted to connect with the extension sluice boxes described presently,and issupplied with water by means of a pipe 21 connecting with thestream `13 or with another source of supply.

The sluice box or flume 18 connects with the sluice boxes 22, which aremade up in sections to form a continuous fiume and thus they may be madeof any length and, as the dredger progresses up stream, the lowersections of the sluice box or fiume maybe re moved and placed next thesluice box 18. This construction is not shown in detail, as the sluiceboxes are not claimed and may be fastened together in any convenientmanner. It is essential, however, that the flume formed by the sluiceboxes be movable laterally and vertically, as well as extensiblelongitudinally, so that the flume may always be in connection with thesluice box 18; and to this end the sluice boxes 22 are hung in yokes 23,see Fig. 5, which yokes connect by pulley blocks 253iL with a trolley23h, and the pulley blocks are of the kind which are well known to thetrade, and which, when adjusted, re main in the position in which theyare placed, and thus the yokes and sluice boxes may be easily held atany necessary height. The trolleys run on cross cables 24 which arearranged at necessary intervals and extend across the pitA 12, thecables being secured to suitable supporting posts 24 on opposite sidesof the pit. The trolleys have cables 25 secured to them at oppositeends, which cables connect with Winches 26 adjacent to the posts 24ELand thus by winding up the Winches on one side of the pit and unwindingthose at the other, the trolleys of the sluice boxes may be shifted asdesired.

The above described arrangement for hanging the sluice boxes is of greatimportance as it enables the boxes to be shifted laterally if desired,so as to make the proper connection with the dredger, and, as the yokesare independently adjustable, it will be seen that even though theground be practically level, the sluice box may be supported so as tomake a steep continuous grade. It will also be seen that when a sluicebox is removed from the lower end of the complete flume, the lastremaining sluice box may belet down until it is at the same height abovethe water as was the sluice box just removed, and the Whole line ofsluice boxes may be correspondingly changed, thus maintaininga uniformgrade. It is clear that a complete fiume may be changed laterally,vertically, or up and down without taking it apart, the only thingnecessary, as the fiume is moved upward being to takea sluice box fromthe lower end of the fiume and transfer it to the upper end. Thearrangement above described also enables the flume or sluice box to beheld at a steep pitch, so that a comparatively large amount ot' gravelmay be washed with a small amount of water.

In starting the work on the pit the gravel raised by the dredger isdumped on the bank of the pit, as shown at 27 in Fig. 2, but as the workprogresses the lower sections ofthe sluice box are removed andtransferred to the upper end and the tailings are dumped into the lowerend of the pit which has been previously scraped, as will be describedpresently; these tailings being prevented from encroaching too far outhe pit floor by means of a submerged dam or crib 28, which is erectedwhile the pit is drained, as will be presently described, and this cribor dam is preferably of openwork, so that it may be cheaply made, boingcomposed of cross poles covered on the lower side by cheap muslin toprevent the fine sludge and slickens from passing through the dam, andthe muslin is protected by boughs sunk and held opposite it.

In carrying out my method,the pitis started and the gravel washed, asspecified, and when the pit has attained a sutlicient size, a channel 29is opened on the upper side of it of sutlicient depth to float thedredger, the dredger is floated into the channel, and a temporary dam 30erected across the mouth of the channel so as to separate it from theworking pit 12. The drain 10 is then opened so as to drain the workingpit, and this enables the thin layer of gravel 3 l, see Fig. 2, left onthe bedrock of the pit to be scraped up by workmen, as shown at 32 inFig. 4, so that when the pit is again fiooded this valuable gravel maybe raised. Meanwhile, the dredger is at work on the channel 29, startinga new pit, and after the bed rock of the tirst pit has been scraped thedrain 10 may be continued across it in the form of a wooden box helddown by bowlders or other means, the dam or crib 28 erected, the pit 12reflooded, the dam 30 removed, and the work proceeded with as before.

When the dredger 17 is to excavate a out ahead into the bank anyconsiderable dis tance, it is necessary to add a number of sluice boxesto the string of boxes of the iiume, but when this cnt has beenexcavated and it is desired to return the dredger and begin a new cut onthe face of the bank, then these added sluice boxes, together with theropes or cables 24 suspending them, would be in the way and prevent thedredger from backing down. This difficulty is met by laying tracks onthe roof of the dredger cabin, upon which run light trucks of anyapproved kind. The head sluice box and the stringers upon which itrests, are lowered until the upper ends of these stringers rest upon thesaid trucks. The yoke supporting the fiume is then removed, the cables24 slackened, and the sluice box running along the track on the roof ofthe dredger cabin, permits the dredger to be backed down until the lowerend of this particularsluice box is reached, when the operation isrepeated, and so on` until the necessary number of sluice box sectionshave been 4re- IOO moved. As many sections of the sluice boxes can betaken down and placed on the cabin roof of the dredger as is desirable,and then the,

dredger may be permitted to drop down stream the necessary distance. Itwill be seen that after the work is well begun, the tailings from thepit being dug, may be deposited in an old pit which has been previouslycleaned out. lf it is considered desirable to work placer gravel by mymethod where the quantity of water obtainable is insufficient to washthe amount of gravel intended to be handled by any of the ordinarymethods, then a steam pump can be placed npon the dredger 17 and thewater pumped from the pit 12 into the sluice box 18, in which, togetherwith the sluice boxes 22, the gravel may be washed.

After the first pit is completed the gravel, tailings and water can bereturned to the working pit 12, and the water used over and over again.The only water lost in this case is that which is let off by the drain10 when it is necessary to drain the pit 'to enable the bed 'rock to becleaned, which is only once or twice during a season. It will be seenthat the grade of the flume may be regulated as the work progresses upstream, by adjusting the height of the cross cables 24 and hangers 23a.Having thus described my invention, I claimvas new and desire to secureby Letters Patentl. The hereindescribed method of placer mining, whichconsists in dredging a pit in the ground being worked, damming thestream and diverting it around the pit, washing the dredged gravel,draining the pit, and then cleaning up the bed rock of the pit andwashing the scrapings.

2. The herein-described method of placer mining, which consists indredging a pit in the working gravel, washing the said gravel, dredginga channel from the working pit, floating the dredger in the saidchannel, drain- .ing the working pit, scraping the bed rock of the pit,reflooding the pit, and dredging and washing the scrapings.

3. The herein-described method of placer( mining, which consists indredginga pit in the working gravel, washing the dredged gravel,dredging achannel opening from the working pit, loating the dred ger insaidchannel, erecting a dam to separate the channel from the workingpit, draining the working pit, scraping the bottom of the pit, erectinga crib across the pit to hold back the tailings,

removing the temporary dam, and dredging and washing the scrapings ofthe pit.

4. The combination, with the dredger, of the sluice boxes in connectiontherewith, formed of removable or separable sections and mechanism formoving-the sluice boxes, substantially as described.

5. The combination, with the dredger of the transverse cables, thetrolleys movable on the cables, the sluice boxes formed of removable orseparable connections suspended from the trolleys, and the sluice box onthe dredger arranged to deliver into the sluice box on the trolleys,substantially as described.

6. The combination with the dredger, and the sluice boxes thereon, ofthe flume of connected sluice boxes or sections, the yokes supportingthe said sections, the cables, and trolleys runnin g on the cables andsu pportin g the yokes, substantially as described.

7. The combination, with the dredger and its sluice boxes, of the flumeof connected sluice boxes or sections, the yokes supporting the saidsections, the cables, the trolleys held to run onvthe cables, and theadjustable pulley blocks connecting the yokes and trolleys,substantially as described.

SAMUEL S. HARPER. Witnesses: Y.

C. E. BALL, JAMES J. BALL.

